I want to extract some information from the info column of my VCF file, when I load my VCF file, I do not have access to my depth (DP) and number of alleles (AN), however, the NS(number of samples for this allele works fine), DP and AN shown as "NA". My vcf file clearly show that neither DP nor AN is empty, here is just one line example of my vcf file, thanks!

According to the archive in the Bioconductor, this should be Version1.8.13. Please let me know if you need additional information that I can provide, I really appreciate your comment. And I am running R in ubuntu